PTOs are used on agricultural vehicles such as tractors to provide power for equipment or implements such as combines, mowers and spreaders. Many modern PTOs are controlled by engaging and disengaging a clutch coupled to the engine of the tractor through an drive train. In at least the higher power tractors, the clutches are hydraulic clutches which are engaged and disengaged using a hydraulic system including appropriate valves and hydraulic fluid.
During cold weather operation of such clutches, there exists a condition whereby the clutch will not engage in a timely fashion when the PTO is turned 0N (i.e. the associated hydraulic valve is opened). This condition is caused by a delay in hydraulic fluid pressurization which is the result of high oil viscosity at cold temperatures. In particular, high oil viscosity substantially reduces the response time for fluid flow when an associated valve is opened. Subsequent to the delay, pressurization will occur and the PTO clutch will engage the PTO with the tractor engine. However, this delay can allow an operator to leave the seat and tractor cab (i.e. operator area) not realizing that the PTO is turned ON, but not engaged.
Accordingly, it would be useful to provide a hydraulic PTO clutch control system which, when the operator leaves the operator area and the PTO is turned ON, warns the operator if the PTO switch is turned 0N within a first predetermined period of time, and operates to disengage the clutch if the operator does not return to the operator area during the warning and within a second predetermined time.